Diagnostic Testing

<span title="">2007</span> <i title="Elsevier BV"> <a target="_blank" rel="noopener" href="https://fatcat.wiki/container/ssdz5shjvrai3ijjkutdhctqam" style="color: black;">Journal of the American College of Cardiology</a> </i> &nbsp;
Bland-Aultman agreement for EF are shown in figures 1 and 2. Conclusion: Two-D speckle tracking can measure ventricular volumes and EF from Bmode images. Automated boundary detection requires only 3 points on one frame, which is less timing consuming than hand tracing, This new technique yields rapid results and agreed well with hand tracing,and may be useful in clinical practice. 7:30 a.m. 806-5 Background: Cardiac dyssynchrony has been measured using several echocardiographic modalities, i.e.
more &raquo; ... M-mode, tissue Doppler and more recently 3D imaging, by analysis of the timing of regional endocardial motion, which are all limited by angle dependence and/or cardiac translation. Accordingly, we developed a new technique based on tissue speckle tracking to measure the temporal uniformity of regional LV wall thickening. Methods: Short axis views were obtained in 3 groups of patients: normal (NL, n=9), dilated cardiomyopathy (DCM; n=7) and regional wall motion abnormality (RWMA; n=5). Images were analyzed using custom software: 6 regions of interest (ROI) were identified; 2 points were placed over the endocardium and epicardium in each ROI (fig 1) and the distance between them was tracked throughout the cardiac cycle, resulting in 6 time curves of regional wall thickening over time, from which the time interval between the R wave and maximum wall thickening was measured (fig 2) . The SD of these time intervals was used as an index of asynchrony (IAsy) and compared between groups. Results: IAsy was significantly shorter in NL group than in DCM and RWMA groups (fig 3, *p<0.05 vs NL; t-test): 33.6±19.8 ms in NL, 133.3±44.4 ms in DCM (p=.0006) and 83.7±32.6 ms in RWMA (p=.0108). Conclusions: LV dyssynchrony can be assessed by quantifying the temporal uniformity of regional wall thickening using tissue speckle tracking, without being confounded by cardiac translation or angle-dependency. 7:45 a.m. Background: The size and location of a region of interest (ROI) across the thickness of cardiac wall could have an impact on quantifying strain values. Methods: 25 pigs (50-55kg) were anesthetized and hearts exposed by midline sternotomy. Short axis views were acquired at mid cavity level directly from the heart surface, using a 10 MHz sector probe on GE Vivid 7 Dimension system. Frequency and frame rate were optimized, achieving axial resolution of 215um and lateral resolution of 345um. 2D speckle based radial strain measurements were taken at comparable points by placing the ROI in subendocardium and then in subepicardium. The ROI was placed in the center between endocardial and epicardial borders. Measurements were taken with 4mm, 5mm and 6mm width of the ROI. Results: Peak strain values were highest in endocardium (16.08±7.63) and lowest in subepicardium (7.65±6.44). Peak strain values in middle myocardium were in between these two values (12.90±6.80). A similar variation in radial strain values was seen (30.90±6.65 in subendocardium, 10.05±5.45 in subepicardium and 22.45±6.55 in mid myocardium). Increasing the width of ROI had little effect on circumferential strain; however, radial strain values were significantly different at different widths of ROI especially in the anterior septal region(18.45±6.55 at 4mm, 20.15±3.95 at 5mm, and 26.75±4.45 at 6mm). Conclusions: This study has shown that strain value varies with size and location of ROI because of regional differences in mechanics between layers. ACC.ORAL CONTRIBUTIONS 806 Advances in Echocardiographic Speckle Tracking Imaging Monday, March 26, 2007, 7:00 a.m.-8:30 a.m. Room 271-273 7:00 a.m. Background: Vector velocity imaging (VVI) can be used to measure LV torsion. We compared VVI and tagged MRI to measure of LV torsion and also assessed the accuracy of VVI of MRI data. Methods: 14 patients underwent standard tagged MRI and 2-D TTE. Tagged MRI and Bmode echo images of LV apex and base were analysed for rotation (rot), torsion (tor) and circumferential strain (ECC). VVI (Siemens, CA) was applied to both MRI and echo images. Results: The table shows the data for rot, tor (difference of the rot normalized to LV length) and global ECC (p=NS). The figure shows an example of tagged MRI and VVI of MRI and Echo. ES freeze frames are shown with ECC curves at the bottom. Conclusions: VVI provides accurate measure of LV torsional dynamics when compared to MRI, and can also be applied to MRI data. Parameters Echo-VVI MRI-VVI Tagged -MRI Apical rotation(Deg) 4.47±1.49 6.85±2.09 5.49±1.36 Basal rotation(Deg) -3.04±0.48 -3.54±0.44 -5.01±0.75 LV torsion(Deg/cm) 1. Background: Two-D strain based on speckle tracking is a new echocardiographic technique, whose utility would be enhanced by automated derivation of LV volume and ejection fraction (EF). Aim: To validate automated boundary detection measurements of LV volumes and EF by speckle tracking. Methods: We studied 71 pts (20 dilated, 11 ischemic and 20 hypertrophic cardiomyopathy, and 20 pressure-overload hypertrophy; 58 ±17 years, 30 F) and 70 normal sunjects (41 ± 16 years, 30 F). End-diastolic volume (EDV), end-systolic volume (ESV), and LV EF were calculated by automated boundary detection using the speckle tracking method requiring only manual placement of 3 points (apex + 2 annular points) on the end systolic image, and compared with routine hand traced volumes using GE VV7 from apical 4-chamber view. Results: Speckle tracking automated boundary detection measurements (EDV=103 ± 66 ml, ESV= 53 ± 57 ml, EF=55 ± 14 %) agreed well with two-dimensional measurements by hand tracing for EDV ( EDV=103 ± 66 ml, Y=1.0X+0.6, r = 0.97); ESV (52 ± 56 ml, Y=1.0X+0.6, r = 0.98), and EF (55 ± 14 %, Y=0.93X+4.6, r = 0.96). The correlation and Background; The severity of myocardial fibrosis may affect the regional contractile function in hypertensives. Method: In 55 patients with hypertension (BP 155/93mmHg, 48±11yrs, EF>55%) and 20 age-matched normotensives, the serum levels of aminoterminal propeptide of procollagen I/III (PINP/PIIINP, marker of collagen synthesis) and tissue inhibitor of matrix metalloproteinases-1 (TIMP, marker of inhibition of collagen degradation) were measured by ELISA & RIA. To assess the myocardial contractile function, the average of negative longitudinal strain of 6 segments on apical 4 chamber view (2DS L ), the average of radial and circumferential strain of 6 segments on mid-short axis view (2DS R , 2DS C ) and basal to apical torsion were obtained by 2D-speckle tracking. Myocardial performance index (MPI, [ICT+IRT] / ET) was calculated. Results: TIMP was higher in patients compared with controls (3.6 ± 0.6 vs 3.0 ± 0.5 µg/L, p<0.001), while PINP and PIIINP were not. TIMP was related to LV mass (r=0.339, p=0.003), MPI (r=0.218, p=0.05) and inversely correlated with E/A ratio (r=-0.243, p=0.034). In patient group, torsion showed positive correlation with TIMP ( Fig A) . 2DS L significantly correlated with TIMP (Fig B) , whereas 2DS R and 2DS C were not. Significant correlation between 2DS L and MPI (r=0.396, p=0.002) was found. Conclusion: Depressed longitudinal strain with compensatory increase of torsion relates to elevated TIMP level representing the extent of myocardial fibrosis in hypertensives with normal EF. 8:15 a.m. Background: Regional radial strain is an important means to quantify ventricular dyssynchrony. A novel approach from routine grayscale echo images, known as speckle tracking, calculates myocardial strain independent of angle of incidence. The aim was to validate this new technique using angle corrected tissue Doppler (TD) strain imaging in an animal model of dyssynchrony. Methods: Ten open-chest dogs had both grayscale and TD mid-LV short-axis echo images (Aplio 80, Toshiba Corp). Right atrial (RA), right ventricular (RV) to simulate left bundle branch block (LBBB) and left ventricular (LV) pacing leads were placed. Timeto-peak strain was measured by angle-corrected TD and speckle tracking using a new program on the same loop and 6 manually drawn regions of interest during 4 different pacing modes (RA-baseline, RA-RV (LBBB), RA-LV, RA-BiV). Results: Of 240 segments, 222 (93%) were analyzed for strain data by both methods; segments with catheter or pacing lead artifacts were prospectively excluded. Speckle tracking and angle corrected TD quantified dyssynchrony for LBBB similarly with maximum strain delay 173±68ms* and 167±72ms*, respectively vs. baseline control 59±44ms and 61±37ms (*p<0.05). Comparative time-to-peak strain overall by each method correlated well: r=0.97, bias of -6±20ms. Conclusions: Time to peak strain assessment by speckle tracking correlated with time to peak strain by TD in an animal pacing model of dyssynchrony, and has potential for clinical applications. Introduction: It is unclear whether the use of F-18-fluorodeoxyglucose (FDG) PET imaging in patients with LV dysfunction and CAD, improves outcomes. Methods: This multicenter trial randomized patients with poor LV function to PET guided therapy versus standard care. Randomization was stratified for 'prior angiography'. Our primary outcome was the composite endpoint of cardiac death, MI, transplantation, or rehospitalization for cardiac cause. Included patients(Pts) had EF<35%, CAD, were being considered for a) Revascularization (RV); or b) heart failure work-up. Exclusions were a) MI within 4 weeks, b) emergency RV, c) severe valve disease, d) unsuitable for RV, e) other co-morbidities. When PET identified viable myocardium, RV was recommended. For control Pts, alternative tests were considered at the MD's discretion. Results: 9 centers enrolled 430 Pts (218 PET, 212 controls). At 1 year, relative risk for the composite endpoint was 0.84 (95%CI=0.63,1.1; p=0.25). When analysis considered 'treatment received', the Hazard Ratio (HR) for FDG PET guided therapy was 0.7(95%CI=0.5,0.99; p=0.046). Intention to treat analysis of Pts without recent angiography (n=199) showed a significant reduction in cardiac death rate with PET compared to standard care (HR=0.37, 95%CI=0.14,0.94; p=0.03). Conclusions: Compared to standard care, PET-guided therapy tended to yield fewer cardiac events at 1 year; and increased survival significantly in Pts without recent angiography. Long-term follow-up is ongoing. ACC.ORAL CONTRIBUTIONS 811 Background: There is a consensus that coronary calcified plaque measured by cardiac CT predicts incident coronary heart disease (CHD) and that the prevalence of calcified plaque varies by race ethnic groups in the United States (US); however, there is sparse data related to the prediction of events in American minority groups. Therefore, the generalizability of associations with CHD to the diverse US population has been questioned. Methods: We examined the impact of coronary calcium (CAC) independent of global risk assessment in the Multi Ethnic Study of Atherosclerosis cohort, a population based sample without CHD at entry, drawn from four major American ethnic groups. Six thousand seven hundred and twenty six participants from six field centers, (mean age 62.1 +/-10.2 years, 50 % women and 38% white, 28% black, 22% Hispanic, 12% Chinese) underwent coronary risk factor evaluation, cardiac CT scanning for CAC measurement using electron beam computed tomography or multi-detector computed tomography, and clinical followup for 35.4 months. Local clinical teams contacted participants or their families every nine months to determine the occurrence of myocardial infarction, CHD death, definite angina or angina requiring revascularization. Results: There were 127 total CHD events of which 72 were hard events (either myocardial infarction or CHD death). CAC hazards ratios (HR) for calcium (per unit change in log transformed calcium score), and for Framingham risk score (unit of 1%), in the combined multi-racial cohort, were 1.45 (95% C.I.:1.33 -1.56) and 1.04 (95% C.I.:1.02 -1.05) respectively. Cox regression of CAC and Framingham risk score as predictors of CHD events in the four ethnic groups resulted in HR for calcium (per unit change in log transformed calcium score) of 1.4 for Caucasians, 1.8 for Chinese, 1.7 for African Americans, and 1.4 for Hispanics (all p<0.001). Conclusions: Greater CAC score, as measured using cardiac CT, is a strong predictor of an increased rate of incident CHD events and provides additional predictive information beyond that afforded by traditional risk factor assessment in four major US ethnic groups. 9:15 a.m. Background: The aim of this study was to assess the interrelationship between myocardial perfusion images (MPI), coronary flow reserve (CFR), coronary artery (CAC) and thoracic aorta calcium (TAC). Methods: In 100 pts (M/F = 56/44; age=57±12 yrs) with intermediate risk of CAD, both CAC and global/regional TAC, and MPI at rest and pharmacologic stress were obtained using Rb-82 PET/16-slice CT. All MPI were visually interpreted quantitatively using a 17 segment model as normal or abnormal (mild, moderate, severe). CFR was measured using the method of Yoshida (JNM 1996). Results: 45 pts had abnormal MPI (mildy in 31 and moderate to severe in 14) whereas 55 had normal MPI. Intraclass correlation coefficients for intraobserver variability for CAC, CFR and TAC were > 0.95 respectively. There was increasing proportion of both abnormal MPI (15%, 46%, and 76%) and moderate-to-severe abnormal MPI (5%, 11%, 35%) with increasing TAC of 0, 1-1000, >1000, respectively. Spearman correlation (Rho) of CFR with CAC, TAC, regional ascending aorta (ASC), aortic arch (ARC), and descending thoracic aorta (DSC) calcium were -0.47, -0.48, -0.31, -0.44, and -0.38, respectively (p<0.005 in all). By multivariate analysis, age was a most potent independent predictor for CFR cut-off value of 2.0 (Odds ratio=0.99, CI= 0.85-0.96; p=0.001) followed by CAC (OR=0.99, CI=0.99-1.00; p=0.04). Conclusions: Global and regional thoracic aortic as well as coronary calcification is inversely related with CFR in intermediate risk pts. 9:30 a.m. Introduction: Coronary artery calcium score (CAC) reflects plaque burden but not necessarily obstructive coronary stenoses. Prior studies of the relationship of CAC to ischemic burden based on SPECT myocardial perfusion imaging (MPI) have shown conflicting results. As pharmacological stress test using Rb-82 PET (RbPET) has superior sensitivity and specificity when compared to SPECT, we studied the correlation between CAC score and presence of ischemia on RbPET. Methods: A total of 230 consecutive subjects had a CAC score determined (Agaston scoring system) using a 16-slice multi-detector CT, followed by a dipyridamole stress MPI with RbPET. Results: The average age was 62.8 years (range 31-90) and there were 109 females (47.4%). The average calcium score was 431 (range 0-5953). There was a statistically significant positive correlation between CAC score and the presence of ischemia on RbPET, r= 0.37 (p<0.001). There was also a significant positive correlation between the presence of ischemia and CAC percentile score (derived from MESA database and adjusted for age, gender and ethnicity), r= 0.36 (p<0.001). On multiple regression analysis using conventional risk factors for CAD, only the presence of diabetes mellitus and CAC were significant independent predictors of the presence of ischemia on RbPET (p= 0.024 and <0.0001 respectively). Conclusion: CAC score is an independent predictor for the presence of ischemia. CAC score should play an increased role in the evaluation of patients with suspected CAD. Background The NCEP ATP III suggests using CAC and hs-CRP in individuals at intermediate risk. The combined effect of "atherosclerotic inflammation", i.e. the combination from CAC and hsCRP, on risk stratification has not yet been tested in an unselected general population. In a cross-sectional analysis of the ongoing population-based Heinz Nixdorf Recall (HNR) cohort study, we analyzed age-adjusted prevalence rate ratios (RR) of CHD. Methods: In the HNR study, 4487 (93.2%) subjects without and 327 (6.8%) of 4814 subjects with CHD (age 45-75 years) were screened including CAC and hs-CRP. Ageadjusted RRs for prevalence of CHD in relation to risk factors were determined. The following CAC and hs-CRP-categories were used: 1) CAC<100, 100-399 and 400 or >75th percentile, respectively, 2) hs-CRP 1 mg/L, 1-3mg/L, >3mg/L, and 3) a combined CAC and hs-CRP score in three groups. Results: RRs for established risk factors including BMI>30, age, smoking, diabetes, hypertension, dyslipidemia, history of stroke or peripheral artery disease (PAD), ranged between 1.29 (95%-CI=1.0-1.7) for BMI>30 in men and 4.95 (95%-CI=1.7-14.4) for a history of PAD in women. For high versus low hs-CRP-values a significant RR was found for women (RR=2.5, 95%-CI=1.3-4.6, p<0.01) but not for men (RR=1.1, 95%-CI=0.8-1.5, p=NS). Highest RRs of CHD were found for high CAC versus low CAC in men (RR=18.2, 95%-CI=10.6-31.3) and for high versus low categories in the combined CAC+hs-CRP-Index in women (RR=11.0, 95%-CI=5.1-23.6, both p<0.0001). We observed strong gender differences as to the effect of different risk factors. However, when the combined index of CAC and hs-CRP was used, prevalence RR were higher than conventional risk factors and gender differences nearly vanished (men: RR=10.7 (95%-CI=6.5-17.5), p<0.01; women: 11.0 (95%-CI=5.1-23.6), p<0.01). Conclusions: Prevalence rate ratios of CHD using CAC and hcCRP were higher compared to established risk factors. Measuring atherosclerotic inflammation may gender-independently improve risk prediction in a general population.
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